Seven antioxidative serotonin derivatives were isolated from safflower (Carthamus tinctorius L.) oil cake. Their structures were established as N-[2-(5-hydroxy-1H-indol-3-yl)ethyl]ferulamide (1), N-[2-(5-hydroxy-1H-indol-3-yl)ethyl]-p-coumaramide (2), N, N'-[2, 2'-(5, 5'-dihydroxy-4, 4'-bi-1H-indol-3, 3'-yl)diethyl]-di-p-coumaramide (3, ) N-[2-[3'-[2-(p-coumaramido)ethyl]-5, 5'-dihydroxy-4, 4'-bi-1H-indol-3-yl]ethyl]ferulamide (4), and N, N'-[2, 2'-(5, 5'-dihydroxy-4, 4'-bi-1H-indol-3, 3'-yl)diethyl]-diferulamide (5), N-[2-[5-(β-D-glucosyloxy)-1H-indol-3-yl]ethyl]-p-coumaramide (6), and N-[2-[5-(β-D-glucosyloxy)-1H-indol-3-yl]ethyl]ferulamide (7). Antioxidative activities of the compounds were measured by the ferric thiocyanate method and the α, α-diphenyl-β-picrylhydrazyl (DPPH) method, and compounds 1-5 were found to have relatively strong antioxidative activity.